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| Carton, Xavier; Ciani, Daniele; Verron, J.; Reinaud, J.; Sokolovskiy, M.. |
| The merger of two identical surface temperature vortices is studied in the surface quasi-geostrophic model. The motivation for this study is the observation of the merger of submesoscale vortices in the ocean. Firstly, the interaction between two point vortices, in the absence or in the presence of an external deformation field, is investigated. The rotation rate of the vortices, their stationary positions and the stability of these positions are determined. Then, a numerical model provides the steady states of two finite-area, constant-temperature, vortices. Such states are less deformed than their counterparts in two-dimensional incompressible flows. Finally, numerical simulations of the nonlinear surface quasi-geostrophic equations are used to... |
| Tipo: Text |
Palavras-chave: Shear/strain flow; Steady states; Vortex merger; Numerical model; Surface quasi-geostrophy; Critical distance. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00323/43460/42864.pdf |
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| Isern-fontanet, J.; Hascoet, Erwan. |
| The noise present in infrared satellite measurements of sea surface temperature (SST) hampers the use of surface quasi-geostrophic (SQG) equations to diagnose ocean dynamics at high resolutions. Here we propose a methodology to reduce the contribution of noise when diagnosing surface vorticity, divergence, and vertical velocity from SST able to retain the dynamics at scales of a few kilometers. It is based on the use of denoising techniques with curvelets as basis functions and the application of a selective low-pass filters to improve the reconstruction of surface upwelling/downwelling patterns. First, it is tested using direct numerical simulations of SQG turbulence and then applied to diagnose low-frequency vertical velocity patterns from real MODIS... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Surface quasi-geostrophy; Remote sensing; Vertical velocity; Ocean submesoscales; Image denoising. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00170/28162/26391.pdf |
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